Program Director/Principal Investigator (Last, First, Middle): MIIIS, D a v l d , A . PROJECT SUMMARY (See instmctions): The use of prebiotics and probiotics to restore a healthy gut microbiota represent a desirable target, but the lack of mechanistically relevant signatures of how specific bacteria interact with the intestinal environment and the host has hindered the development of effective and well-characterized prebiotic and probiotic treatments. The long-term goal is to translate the successful strategy of mammalian lactation, shown using human milk glycans, to the development of targeted, effective synbiotics by using plentiful and available bovine milk glycan streams. The overarching hypothesis to be tested is that the evolutionary relationship between infant-borne bifidobacteria and bovine milk glycans and glycoconjugates produce a synergistic human milk glycan-like phenotype that can effectively colonize, restore a healthy gut microbiota and induce host response to better protect epithelial barrier function and thus improve health outcomes. First, the team will address whether in infant-borne bifidobacteria species, complex milk glycoconjugates induce specific glycosyl hydrolases and transporters that are necessary to consume these complex substrates. Milk glycoconjugate catabolism by infant-borne bifidobacteria will be examined by detailed transcriptomics, specific enzymatic and transporter analysis, and glycoprofiling to identify precise links between glycan components and their cognate bifidobacterial processing mechanisms. Second, the research team will determine whether select infant-borne bifidobacteria that consume complex milk glycoconjugates compared to simple sugar substrates are more effective in inducing a protective response within the host epithelium. Measurements of bifidobacterial adherence, improved barrier function, release of inflammatory mediators and activation of enteroendocrine cells will be obtained from gut epithelial and enteroendocrine cells in vitro and ex vivo in rat small and large intestinal tissue. Finally, the team will determine whether modulation of intestinal function by application of synbiotic milk glycan- and glycoconjugate-consuming bifidobacteria improves outcomes in a rodent model of intestinal and metabolic disease. The significance of this project is that it will take a systematic and mechanistic approach to understanding the synbiotic relationship. RELEVANCE (See instmctions): The gut microbiome is a crucial component of human health. Safe and effective approaches for correcting, maintaining, and guiding establishment of a healthy gut microbiota, particularly in infancy and early childhood, are needed. The project is relevant to NCCAM's mission because it supports a portfolio of synbiotic interventions for improving health, with mechanistic signatures of biological effects.